Hypoxia
The Doyle family
farms along the Mississippi River in Iowa. Their corn and soybean
crops grow in rich river soil created by centuries of
deposited by glaciers and the Mississippi's flood cycles. The Dauphin
family lives near the Mississippi River's delta, which is south
of New Orleans. Instead of land based crops, the Dauphins harvest
fish, shrimp, and crabs from the river's rich delta waters. Both
families rely on the river to make their living. And they find themselves
pitted against each other for survival.
The "farmers
of the sea" are facing a serious threat to their livelihood—hypoxia.
Hypoxic waters contain too little oxygen to support aquatic life.
Hypoxia begins when excess nutrients are carried to a body of water.
The excess nutrients trigger huge algae blooms. (Algae are small
aquatic plants that reproduce quickly, spreading or "blooming"
in the water.) The blooms grow, die and decay. The decaying process
uses up oxygen in the water, leaving too little to support other
aquatic life. The hypoxic conditions existing in a huge area of
the Gulf of Mexico have created the "."
Some research
blames hypoxia directly on upriver farmers, like the Doyles. Why?
Many land-based farmers apply to their fields to boost
plant growth and increase the size of harvests. Some researchers
say that too much of this nitrogen is running off farm land into
streams and rivers that feed the Mississippi River, ending up in
the Gulf and triggering the cycle that leads to hypoxia and the
Dead Zone.
What
Can be Done?
Research suggests that farmers drastically cut the amount of nitrogen
they apply to their crops and plant buffer zones near streams and
rivers. (Buffer zones are areas of vegetation planted between crops
and waterways.) Farmers are resisting these suggestions because
they say it is a double cut—they would lose crop land to create
the buffer zones and have lower yields if they apply less nitrogen.
A more drastic
suggestion is that millions of acres of farmland get turned back
into . Wetlands act as a natural filtration system. They
keep fertilizer runoff from getting into the water by absorbing
the .
Farm supporters
point out that the chemicals they apply aren’t the only source
of nitrogen, or the only problem. Animal waste contains nutrients,
and urban landowners use chemicals as well. Upstream farmers want
research to be done to see how dikes and channeling affect the river.
They also point out that thousands of acres of gulf coast wetlands
are lost each year, removing the natural nitrogen filters at the
mouth of the river.
Until a solution
to hypoxia is found that is agreeable to all those involved, the
farmers of the land and the farmers of the sea will stay locked
in their struggle for survival.
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